In the last few years, many smart, innovative design projects have debuted that could potentially change the world as we know it -- many of which were covered here on TreeHugger. As part of its design triennial exhibition series, the Cooper-Hewitt, National Design Museum asks "Why Design Now?," answering with work from designers "addressing human and environmental problems across many fields of the design practice, from architecture and products to fashion, graphics, new media, and landscapes." This is an important show of design with a social purpose, but also a presentation of very cool stuff. Here's a preview of the exhibition, which opens tomorrow, May 14 and is on view through January 9, 2011.

The MIT CityCar

MIT's Stackable, Foldable "City Car", which we wrote about back in 2007, is "a lightweight electric vehicle that can be cheaply mass-produced, rented by commuters under a shared-use business model, and folded and stacked like grocery carts at subway stations or other central sites."